Control system and telemetering circuit



y 1947- w. A. DERR 2,420,871

' CONTROL SYSTEM AND T ELEMETERiENG CIRCUIT Filed Feb. 1, .1945 5 Sheets-Sheet 1 WITNESSES: INVENTOR fi 7% W/ Ward/7 Derr:

y w q BY May 20, 1947. I w. DERR 2,420,871

CQNTRQL SYSTEM AND TELEMETERING CIRCUI T Filed Feb. 1, 1945 s Sheets-Sheet s Der/ice v 3/46 WITNESSES:

INVENTOR 57 Me v ATTORN Patented May 20, 1947 common SYSTEM AND TELEMETEBING CIRCUIT Willard A. Dcrr, Wilkinsburg, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 1, 1945, SerialNo. 575,631

19 Claims.

My invention relates, generally, to supervisory control systems, and has reference in particular to supervisory control systems for providing telephone and telemetering circuits.

Generally stated, it is an object of my invention to provide a simple and inexpensive supervisory control system having provision for telemetering and telephone operations in addition to other supervisory and control functions, which system shall be easy to operate.

More specifically, it is an object of my invention to provide for selecting metering or telephone communication points in a supervisory control system and rendering the supervisory control equipment inoperative during metering and telephone operations.

It is also an object of my invention to provide for resetting and looking out the supervisory control equipment at both the dispatching office and remote stations, as soon as the supervisorychannel is prepared for telephone communication.

Another object of my invention is to provide for using the usual long pulse reset signal in a single frequency carrier supervisory control system, wherein the carrier frequency is also used for telephone and/or metering operations.

Yet another object of my invention is to provide for telephone and telemetering operations in a carrier frequency supervisory control system with a minimum of equipment.

Still another object of my invention is to provide for automatically reconnecting the signal channel to the supervisory equipment and effecting reset of the supervisory control equipment at the end of a telephone communication to restore the supervisory equipment to normal.

A further object of my invention is to provide for selectively connecting a, supervisory control signal channel for an impulse metering operation, and for preventing operation of the supervisory control line relays at the dispatchin ofiice and at the remote station to prevent interference during the metering operation.

An important object of my invention is to provide for maintainin the supervisory release relays at the dispatching ofiice and at the remote station in the deenergized position during a telephone conversation so as to insure looking out the supervisory equipment.

It is also a further object of my invention to provide for interrupting the operating circuits of the supervisory line relays during metering operations so as to prevent interference with the supervisory equipment.

Other objects will, in part, be obvious and will, in part, be explained hereinafter.

According to my invention, telemetering and telephone communication are efiected in a super-' visory control system through separate points of the system. A telephone circuit is completed by a transfer relay through the carrier supervisory equipment in response to completion of a supervision code which is initiated by the called operator answering. At the same time the usual relatively long reset impulse is sent and the supervisory release relay'is' deenergized so that the supervisory equipment is locked out during telephone conversation. Upon thetermination of a conversation, the release relay is reenergized and another relatively long reset impulse signal is sent from the dispatching ofiice to restore the supervisory equipment to normal when the phone is rBStOI'Gd to the hook. Inorder to provide for effleeting restoration of thes ystem'to normalafter a metering operationby the customary long reset impulse, the line relays are rendered inoperative during the metering operation by opening the operating circuits therefor. Reset after a metering operation is efiected in the usual manner.

For a more complete understanding of the nature and scope of my invention, reference may be made to the following detailed description, which may be-studied in connection with the accompanying drawings, in which Figures la and lb together provide a diagrammatic View of the dispatching office equipment in a supervisory control system embodyin the invention in one of its forms, and

Fig. 2 is a diagrammatic view of the remote station equipment of the supervisory control system, associated with the dispatching office equipment shownin Figs. la and lb.

Referring to Figs. la and lb, the reference numeral Ill may denote, generally, supervisory sending, receivingfland common equipment at the dispatching office of a supervisory control system embodying the invention. The supervisory equipment may, in general, be substantially similar to that described in detail in Patent No. 2,091,301, which issued on August 31, 1937, to H. P.Boswau. For the purposes of simplification, that part of the Boswau equipment which has not been changed in any respect, is represented, generally, by the enclosure I Lwhile theequipment of the Boswau patent to which any changes have been made, and any additional equipment, are shown in detail, adjacent thereto. Such relays and other apparatus, as are similar to those of the Boswau patent, bear the same designations as in' the Boswau patent. All additional equipment is designated by'numerals notappearing in the Boswau patent.

Instead of having the impulse-sending relay 29! of the Boswau patent energize a pair of line conductors by connecting them to a direct current source as inthejBoswau patent, the, im pulse-sending relay 2M is, in the present application, arranged to key a carrier transmitter l2 which may be connected to the conductors E3 of a power system or the like, by suitable coupling 3 means [4 comprising, for example, a tuned circuit of capacitors I5 and inductance coils it. The line relay 2% of the present application may be arranged for operation through a carrier receiver i8 which may likewise be coupled to the conductors l3 through the coupling means It.

Referring to Fig. 2, the reference numeral 253 may denote, generally, the supervisory control sending, receiving, and common equipment at a remote station of the supervisory control system. The equipment, 20 may, a in the case of the equipment at the dispatching office, be substantially similar to that described in the Boswau patent. Such equipment, as is identical with that of the Boswau patent, may be represented by the enclosure 2|, while that which has been changed in any respect, and any additional equipment, are shown in detail adjacent thereto.

As in the case of the equipment at the dispatching ofl'lce, the impulse-sending relay 49! may be arranged for operating a carrier frequency transmitter 22 which may be coupled to the conductor l3 by coupling means IA. The line relay 409 may likewise be connected for operation from a carrier frequency receiver 28 which may also be coupled to the conductors it, through coupling means l4. 7

Referring again to Figs. 1a and 11) it Will be seen that in order to provide for transmitting metering indications from the remote ofiice to the dispatching office, point I of the supervisory control system of the Boswau patent may be used as a metering point, so that the point selection key HE, may be designated as the metering key. Means, such as the indicator 3%], may be provided at the dispatching ofiice for operation under the control of a metering impulse receiver relay 32 for indicating the value of a quantity to be metered. The impulse receiver relay 32 may be connected to the carrier receiver J8 under the control of a metering transfer relay 33, which may be energized under the control of the metering supervisory point relay I33. The indicator 30 may be of any suitable type being, for example, responsive to an impulse of the carrier frequency in each of successive cyclic intervals of predetermined duration, said impulses being of different durations dependent on the amount of the quantity to be metered.

Referring to Fig. 2, the reference numeral 35 may designate a metering device for measuring at the remote station the value of a quantity to be metered. The metering device 35 may be of any suitable type being, for example, provided with contact means 350. for providing an impulse in each of a number of cyclic intervals of predetermined duration, said impulses being of difierent durations dependent on the value of the quantity being metered. In order to provide for connecting the metering device 25 to send such metering impulses whenever the metering point is selected, a metering impulse relay 36 may be provided for operating the carrier transmitter 22 to transmit impulses of different predetermined durations in each of successive cyclic intervals in response to operation of the metering device. The metering device 35 may operate continuously during a metering operation so that a meter control relay 38 may be provided for completing the operating circuit of the meter impulsing relay 36, only when the metering point relay 309 operates in response to a selection of the metering point from the dispatching cflice. Auxiliary metering control relays 39 and 49, which may be of the delayed drop-out type, may be pro- I dispatching office is operated. An energizing circuit for the individual point relay I29 is provided through moving contact H5, back contact and armature 229 of relay 218, and back contact and armature 230 of relay 2!! to indirect positive through circuits of the equipment in the enclosure ll, so that the point relay locks in over its front contact and armature i29a to indirect positive. At the same time, an energizing circuit is provided for the auxiliary start supervisory relay 2H5 from indirect positive through moving contact H6 and front contact of key H4, conductor ll, back contact and armature 23d of relay 2|8, back contact and armature 233 of relay 2| 1, through the operating winding of the auxiliary start relay 2 l 6.

Operation of the individual point relay I29 connects the operating winding of the supervisory start relay 2 is to negative through front contact and armature i290, and conductor 42. This completes the operating circuit for the supervisory control start relay 2i8 which starts the point selection code for selecting the metering point at the remote station. The point selection code is terminated in the usual manner after sending one operating impulse. The point relay 383 at the remote station operates upon the termination of the point selection code and the point selection check code is sent in the same manner as described in the Boswau patent.

Upon the receipt of the point selection check code at the dispatching office, the metering point relay E33 operates and connects the indicator .30 to a source of alternating current through armatures i33e, IBM and front contacts. At the same time, the metering lamp lfs'i lights, and the operating winding 35a of the indicator is connected to a front contact of the metering impulse receiver relay 32, through front contact and armature i330, and conductor 23, so as to prepare the indicator for operation in response to impulses received from the remote station. An operating circuit is also provided for the metering transfer relay extending from negative through the operating winding of the relay, conductor 44 through armature l33b and front contact of the point relay I33, conductor Q5, and back contact and armature Zid of the reset relay 244 to indirect positive. Operation of the transfer relay 33 interrupts the operating circuit for the line relay 2% at armature 33a and back contact to render it inoperative and completes an operating circuit for the metering impulse receiver relay 32 from the carrier receiver I8 through armature 33a and front contact.

At the remote station, operation of the point relay 309 in response to receipt of the point selection code connects the impulse metering device 35 to a source of alternating current through armatures 3890 and 309d for energizing the operating motor thereof and, at the same time connects the operating winding of the metering impulse relay 36 to the impulse metering device 55 through armature 3955b and front contact. Operation of the metering impulse relay is prevented during transmission of the supervisory point check code, since the meter control relay 38 holds the operating circuit open. During the transmission of the point check code the transfer relay 4513 providesan energizing circuit :for the auxiliary metering control; relay 40, 'iextending through armature 309a andfront contact, andfront contact and armature 4,836. Relay 4,0. picks up auxiliary metering control relay 39. When the transfer relay 403 of-the supervisorycontrol equipment deenergizes at the end of theipoint selection check d fthe n eizing circuit for theauxiliary meter control relay 40is interruptedat armature 403a and front contact.

The control relay ilremains'in the energized position for a predetermined time interval and then returns to the deenergized position interrupting the energized circuit for the auxiliary control relayts at; armature 49a andfront contact. However, the auxiliary control relay 39 remains in the energizedposition for a predetertime the metering'impulse relay 36 operates, the carrier transmitter 22 is energized through arma-' ture 36b and front contact to transmit a carrier frequency impulsealong the conductor's [3. Each A b,ellrz54.gmay be provided forsignalling the-o1 eratoryvherracallisbeing received.

1 In iorder tovprovidefor telephone communication-roverthersignal"channeh a point of the supervisorycontrol system may be used for setting up a telephone circuit. For-example, point 4=of ping -thenpoint supervisory relay. I'3l to provide the supervisory control systennas shown in the Boswauxpatent, may be adapted for'selecting a telephone point atrtheremote station and providinga telephone communication channel lootween-the stations; Instead'of initiating the operation by the use of'acpoint key, such as'the key li214cshown .inthe Boswau patent, the hook switch-"53 :may-rbeutilized in conjunction with auxiliary telephone relays 5B and 51 for dropfor--initiating- "a telephone operation. A reset control relay 58-may1 be provided 'for effecting reset "of. the-supervisory control equipmentrat the commencement :of a telephone conversation in order to preventoperation of the carrier transmitter during :phoneconversation from operating :thesupervisory control equipment. .An auxiliary relay 5 9-may be provided for controlling the-operation -of ithe'bell and controlling .the transfer. to telephoneoperation.

Anadditional auxiliary reset relay 6!] may be provided for resetting the supervisory control equipment at the end of a telephone'conversation-so as to restore 'it to anormal condition for performing other supervisory and control functime the metering impulse meter operates, the

operating circuit for the carrier receiver 28 is interrupted, at armature 36a and back contact soas to prevent operation ofthe'line relay 68.

At the dispatching office, the metering impulse receiver relay 32 operates each time a carrier frequency impulse is received by the carrier receiver It. The line relay 29llis inoperative since its energizing circuit is held open during metering at armature 33a. The energizing circuit for the operating winding a of. the metering indicator Sills, accordingly, energized for a predetermined time in each cyclic interval, depending on the value of the quantity being metered, so as to give an indication of the quantity being metered. The operating circuit extends from negative through the operating winding 39a, frontcontact and armature I330 of the point relay, conductor 43, andfront Contact and armature .3241. of the metering impulse receiver relay to direct positive At the end of a metering operation, the supervisory control equipment may be reset by operating the reset key in the usual manner. If the release key is' held down during anonpulsing period of the impulse transmitted, the line relay 4H0 picks up and drops the release relay 402. Upon release, the point relays and the metering transfer relays are .deenergized and the supervisory equipment is restored to a normal operating condition.

Referring to Figs. 1a and 1b, the reference numeral 50 may denote, generally, telephoneequipment whichis disposed to be used in conjunction with the carrier receiver l8 and carrier transmitteriz .over the signal channel of the supervisory control system. The telephone equipment may comprise ahandset 5| which may be connected to the carrier receiver and carrier transmitter through a modulator 52. Means, such as the hook switch 53,'may be provided in conjunction with thehandset for controllingthe operation .of the supervisory control equipment.

tions'as'may be desired. Means, such as the transfer relay 62, may be providedfor operation under the control of the auxiliary relay 59, for

U efiecting connection of the carrier frequency transmitter l2 for control by a push-to-talk switch -63 during telephone conversation. In order to prevent interference of the carrier frequency transmitter by the supervisory control equipm'entduring a telephone conversation, the transfer relay 62 maybe arranged to disconnect the supervisory release relay 202 from direct positive at the armature 620, during the reset pulse and keep it disconnected throughout the telephone operation.

At the remote station, as shown in Fig. .2,,telephone equipment 65 comprising a handset '66 with a hook switch l3! and bell 68 may be ar ranged for operation in conjunction withthe carrier transmitter 22 and receiver 28 by means of a modulator 69 through circuits provided by the point relay 3) at point 4 of the supervisory control equipment. The auxiliary re1ay3l4 normally used in conjunction with the auxiliary switch 3 2| of the Boswau patent, may be. arranged for operation under the control of the hook switch 61 for initiating a telephone point selection operation from the remote station and controlling operation of the bell on an incoming call. A transfer relay 10 may be provided "for transferring the carrier transmitter 22 to the operation of a push-to-talk switch 12 for use in telephone conversation. The transfer relay 1!) may likewise provide for looking out the supervisory control-equipment at the remote station during-a telephone conversation by removing direct positive from the supervisory release relay MlZ-atarmature 10c and back contact.

In operation, if the operator at the dispatching office desires to call the remote station he merely liftsthe handset 5| from the hook. An obvious circuit is thereby provided through the hook switch 53 for energizing the auxiliary-start relay 56. The auxiliary start relayifipicks up andinterrupts-the energizing. circuit 'for the time delay auxiliary start relay '51 which remains in the energized position for a predetermined time. Accordingly, a shunting circuit is provided for a predetermined interval of time for the telephone supervision point relay l3l, extending from indirect positive through armature 56a and front contact, armature 51a and front contact, through the operating winding of the telephone supervision relay IM to direct positive.

Relay I31 drops, connecting negative polarity to the supervisory start relay 2l8 to complete its energizing circuit from armature l3lb through conductor 42, the operating winding of relay 2 l8, and thence through a circuit shown and de scribed in detail in the Boswau patent. The reset control relay 58 is energized through armatures 59b and 56a to direct positive at armature I301) and back contact. At the same time, an energizing circuit is provided momentarily for the auxiliary start relay 2l6 through armature 57b and front contact, front contact and armature56c, conductor 4|, back contact and armature 234, back contact and armature 233, and operating winding of the auxiliary start relay 2l6. Accordingly, a point selection code is transmitted in the usual manner which results in the operation of the point relay 3I0 at the remote station.

The point selection check code is thereupon returned in the usual manner. This results in the point relay I34 at the dispatching office being picked up. A circuit is, accordingly, provided through armature I69 and front contact to indirect positive on the counting chain for energizing the operate code start relay 2|5 which, accordingly, transmits an operate code of five operating impulses. Receipt of the operate code at the remote station results in operation of the operate relay M4 in the Boswau patent which places direct positive on the telephone bell 68 through a circuit extending from the bell through front contact and armature 3M of the point relay 3H1 to the close bus and direct positive through front contact and armature 450 of the operate relay 4M of the Boswau patent (now,

shown).

The bell rings until the operator at the called station answers. Lifting of the handset 66 from the hook switch 6'! interrupts theoperating circuit for the bell by interrupting the energiz supervisory code terminates, an energizing circuit is prepared for the telephone transfer relay 1!] through a circuit extending from negative through the operating winding of the transfer relay 10, through front contact and armature 343d of the point supervisory relay, front contact and armature 3540 of the telephone point relay, back contact and armature 603a to the back contact of armature 42l of the supervisory release relay 462 to direct positive. The transfer relay cannot, however, operate since its energizing circuit is held open at armature 42| until the reset pulse is transmitted from the dispatching office to drop relay 402. 7

At the dispatching ofiice, receipt of the operrelay 62 extending from negative through operating winding of the transfer relay through front contact and armature 56b of the auxiliary control relay 56, and front contact and armature 59a of the auxiliary relay 59 for connecting the telephone for conversation.

The reset control relay 58 drops at about the same time and connects in direct positive to the supervisory reset relay 2! through armature 58a and back contact, front contact and arma ture 2|6d of the auxiliary start relay 2l6, conductor 13, front contact and armature 224 of the battery supervision relay 213, to the operating winding of the reset relay 2H1. A reset pulse is, accordingly, sent for restoring the supervisory equipment to normal. At the termination of the reset pulse, the release relay 202 remains in the deenergized position locking out the supervisory control equipment since the energizing circuit, therefore, is held open at armature 62c and front contact of transfer relay 62.

At the remote station the energizing circuit for thetransfer relay 10 is completed when the supervisory release relay 402 drops during the reset pulse from the dispatching office. The handset 66 is connected to the modulator 69 and the carrier transmitter 22 is connected for control by the push-to-talk switch 12 through armatures H112 and Illa. The supervisory equipment 20 is locked out of operation by removing direct positive from the supervisory release relay 402 at armature 100. Telephone conversation may now be carried on from either station by pushing the push-to-talk switches 63 and 12, which energize the carrier transmitters I 2 and 22, respectively, when it is desired to talk from the dispatching office or the remote station. The auxiliary reset relay 60 is picked up through armature 62c and front contact of the transfer relay. It looks in through armature 60a and front contact and back contact and armature 21412 of the supervisory reset relay.

At the end of a telephone conversation, if the dispatcher hangs up, the energizing circuit for the auxiliary start relay 58 is interrupted at the hook switch 53. The auxiliary start relay drops, interrupting the energizing circuit for the transfer relay 62 at armature 56b. The auxiliary start relay 5! is energized over an obvious circuit extending through armature 56a and back contact of the auxiliary start relay 56. When the transfer relay 62 drops, the release relay 202 is energized and direct positive is reconnected over armature 228. A momentary circuit for the reset relay 2 l4 isrprovided through armature b and front contact, conductor 13, front contact and armature 224 of the battery supervision relay 2l3 through the operating winding of the reset relay 2M, and the reset relay operates to transmit a relatively long reset impulse to restore the supervisory control equipment at the dispatching oflice to normal.

Since the operator at the remote station has not returned the handset to its hook, the supervisory equipment at the remote station remains locked out, and the reset impulse transmitted relay 3M atthe remote station. The energizing.

circuit for the telephone supervisory relay 313 is interrupted at armature 348 so that the phone point supervision relay drops and initiates the sending of a point supervision code in the usual manner; Since the supervisory equipment at the dispatching oiiice is reset, the telephone point at the dispatching office is selected in the usual manner and 'a point selection check code is sent from the dispatching office. At the termination of the point selection check code, the point relay 3l0 operates and a supervision code is sent. Relays I30 and 13! pick up and a reset impulse is transmittedfrom the dispatching oihce in the usual manner resetting both the dispatching office and'the remote station supervisory equipment.

If the operator at the remote station should return his handset tothe hook switch first, the telephone relay 3 is dropped as usual and the telephone point supervisory relay 3l3 sends a 25 point selection code in the usual manner. However, since the supervisory equipment at the dispatching, office is still lockegiout, nothing happens. Upon the dispatcher returning his handset to the hook switch, a reset pulse is sent as previously described. However, since the auxiliary phone relay 3M is down, a point selection code is transmitted 'hy'the remote station in the usual manner after reset is effected from the dispatching office. The dispatching. ofiice and remote station supervisory equipments operate in the usual manner'to send point check and supervisory codes terminating in a long r. es et impulse. The supervisory equipment is .thusrestored to normal for efiecting subsequent supervisory or control operations.

If telephone communication is initiated from the remote station, liftingof the handset 66 from the ,hook switch 6-! picks up the telephone relay 314 and interrupts the energizing circuit for the telephone supervision relay 3| 3 at armature 34,8.

A Accordinglya point selection codeissentout from the remote station in the usual manner, which is received at the dispatching. office and results in operation of the point relay 13,4. A point selection check code is sent in theusual manner whereupon the point relay 3H! operates to send a supervision code. an energizing circuit is thereupon provided for the telephone bell at the dispatching ofiice through the point operate relay I30 atarmature l-3ll ,b an d front contact.

When the operator at the dispatching office answers the telephone and lifts the handset I, the hook switch-53"providesj an energizing circuit forthe auxiliary start relay 56'. Auxiliary relay 59 is thereupon energized through front contact and armature-Biid. Relay 59 picks up, opening the-bell circuit-at armature 59c, so that ringing of'the bell is terminated. -A circuit for the transfer' relay 62 is provided through armature 55b and:: 59a',.and the reset control relay 58 drops." A resetepuise is. sent by the reset relay 2"l'4"as previously describcd, .and the transfer relays 62 and l0.-both.-.operate toconnect the telephone equipment-for. operation and: tolock the supervisory equipmentout.

-;From;.theaboyedescription and the accompanying.:drawings, it will. be apparent'that I haveprovidedzzfor telephone. and telemetering operations in. a, supervisory control system wan an absolute minimum of equipment. During operation of the carrier transmitter for either telephone or telemetering operation, the supervisory equipment is rendered substantially inoperative. 5 Accordingly, no additional equipment is necessary for providing for reset of the supervisory equipment, and the usual long reset impulse may be used, since the supervisory equipment is not required to distinguish thereset impulse from the 10 telemetering-impulses or impulses of carrier dur: ing telephone operation.

Since certain changes may be made in the abovedescribed construction and different embodiment of the invention maybe made without departing from the spirit and scope thereof, it is intended that all of the matter contained in the above description and shown in the accompany ing drawings shall be considered as illustrative and not in a, limiting sense.

I claim as my invention:

1. In a signal system for a control office and a remote station connected by a singlesighal channel, a carrier transmitter and a carrier re eceiver at both theoffice and the station coupled to the signal channel and' operating on thesame frequency, supervisory control means atboth the office andthe station including sending'eq'uipment for operating the transmitters and receiving equipment operated by the receivers for selectmg any of a number of different control and supervision points, means selectable through a selection point of the supervisory control equip-- ment for operating one of the carrier transmitters independently 'of the supervisory control equipment for performing a predetermined'function; and means. for preventing normal operation of the supervisory control receivin equipment in response to' operation of. the" carrier transmitter during the performance of said function.

2. For use in a signal system for a controloffice and .a remotestation connected byr'a single signal channel, a carrier frequency transmitter and a carrier frequency receiver-coupled tolthe channel at both the office and ,the station, supervisory sending means controlling the transmitters'and supervisory receiving means normally controlled by the receivers at the ofiice and at the station for selecting different of a plurality of selection points'at the station or office, means atthe 'ofii'ce and .the station for selectively operating the supervisory equipment to select a point for performing a function. requiring operation of one or the other of the carrier transmitters, and means responsive to the selection of said point for controllingthe operation of the carrier transmitterin.the'performance of. said function and rendering. the supervisory receiving equipment non-responsive to said carrier operation.

.3..In a signal system for an ofiice and a remote station connected by a signal channel, a carrier frequency transmitter and a carrier frequency receiver coupled to the channel at both the office and the station, supervisory control means at the ofiice and the station including sending means for operating the transmitters to transmit impulse signals and receiving means normally for operation from the carrier receiver in response toirnpulselsignals of the 'carrierirequency, said supervisory control means being norm-ally reset by a relatively long impulse signal at the termination of an-o-peration, means for selecting a predetermined point at either the office'or station'ior performinga function requiring operation of the carrier transmitter over relatively 11 long periods longer than the reset pulse, and means responsive to the preparation of the signal channel for such operation of the transmitter for preventing operation of the supervisory control means during the performance of such a function.

4. In a signalling system for a dispatching office and a remote station connected by a signal channel, supervisory control sending and receiving equipment at the ofiice and station, a carrier transmitter for operating over the channel controlled by the sending equipment and a carrier receiver for operating the receiving equipment at both the dispatching office and remote station, telephone equipment at the dispatching ofiice and the remote stationfor operating over the channel through the carrier transmitters and receivers'through a point of the supervisory system, and means for locking out the supervisory sending and receiving equipment to prevent operation thereof by the carrier transmitters during a telephone communication.

5. For use in a signalling system over a single signal channel between an oflice and a remote station, telephone transmitting and receiving equipment at the ofiice and station, a carrier transmitter and a carrier receiver coupled to the channel at the oflice and the station operating on a common frequency, supervisory control means at the ofiice and remote station including line relays operated by the carrier receivers and impulse relays for operating the transmitters to produce impulse signals and point selection equipment for providing a telephone circuit over the channel, means responsive to the answering of the operator at the remote station for looking out the supervisory equipment during a telephone conversation, means responsive to the termination of a telephone communication for sending a reset impulse to restore the supervisory equipment to normal.

6. The combination in a signal system for an ofiice and a remote station connected by a single signal channel, of telephone equipment including a transmitter and receiver at each of the office and station, supervisory control sending and receiving equipment having a plurality of points including one for establishing a telephone circuit over the channel, means responsive to the establishment of a telephone circuit over the channel for rendering the supervisory equipment inoperative during a telephone conversation, and auxiliary reset means responsive to the termination of the conversation to transmit a reset impulse and restore the supervisory equipment to normal.

'7. In a supervisory control system for a control oflice and a remote station connected by a single signalling channel, supervisory control sending and receiving equipment at the oflice and station having a plurality of selection points, a carrier transmitter coupled to the signalling channel at the office and station operated by the supervisory sending equipment on a common carrier frequency for transmitting signal impulses over the channel, a carrier receiver coupled to the channel at the ofiice and station for operating the supervisory receiving equipment in response to impulses transmitted by the transmitters, telephone equipment at the ofiice and station, means at the oflice and station for initiating a point selection through the supervisory equipment, means responsive to the operator at the station answering for transmitting a supervision code to effect reset of the supervisory equipment, means responsive to the termination of the supervision code for connecting the carrier transmitter for telephone operation and locking out the supervisory equipment, and circuit means responsive to the termination of a telephone conversation for restoring the supervisory equipment to normal.

8. The combination in a signal system for a control ofiice and a remote station connected by a signal channel, of telephone transmitting and receiving equipment at the office and station, a carrier frequency transmitter of a common frequency coupled to the channel at each of the of'rlce and station, a carrier frequency receiver coupled to the channel at each of the office and station for operating on said common frequency, supervisory sending and receiving equipment at each of the office and station for operating the transmitters and operation by the receivers, said supervisory equipment having a plurality of selection points including one for providing a circuit for the telephone equipment over the signal channel, and control means responsive to the selection of a telephone circuit over the channel for connecting the carrier transmitters for operation under the control of the telephone equipment and render the supervisory equipment nonresponsive to carrier frequency impulses, said control means being responsive to the termination of a conversation to restore the supervisory equipment to the control of carrier frequency impulses.

9. A supervisory control system for a control ofiice and a remote station having impulse metering means at the station and impulse recording means at the office together'with telephone receiving and transmitting means at both the office and station comprising, supervisory control sending and receiving equipment at the office and station having a plurality of separate selection points including one for providing a telephone circuit and another for providing an operating circuit for'the metering means. and reset means for sending a relatively long impulse signal for restoring the supervisory equipment to normal. means responsive to the selection of the telephone point for sending a supervision code to reset and lock out the supervisory control means at the ofiice and station and connect the transmitter for operation with the telephone equipment, additional means responsive to selection of the metering point for disconnecting the supervisory receiving means from the receiver and connecting the carrier transmitter for operation with the metering means, and means for operating the reset means at the termination of a metering or telephone operation to restore the supervisory equipment to normal by means of the long impulse signal.

10. In a carrier frequency supervisory control system, supervisory control sending and receiving means at a control office and at a remote station having a plurality of selection points for providing circuits over a single signal channel for performing different functions, a carrier frequency transmitter and a carrier frequency receiver of the same frequency at each the control office and remote station operated by the sending means and arrangedto operate the receiving means respectively, metering means at the remote station operable in response to selection of a metering point to effect operation of the remote station carrier transmitter to transmit a plurality of impulse signals over the channel indicative of a quantity to be metered,means at the office operable under the control of the carrier frequency receiver at the ofiice in response 13 to said impulses to indicate the value of the quantity metered, and means at the ofliceresponsive to said impulses upon the selection of the metering point to disconnect the supervisory receiving means from the receiver.

WILLARD A. DERR.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Affel Dec, 18, 1928 Baughman July 16, 1940 Baughman Dec. 10, 1940 Blakeslec June 12, 1945 

